Method of producing slot units



Nov. 2 1926.

T. W. CASE Filed June l, 1925 METHOD OF PRODUCING SLOT UNITS Illl I.||IL ZZ/WENTOR E N n w .Patented Nov. 2, 1926.

UNITED STATES PATENT OFFICE.

THEODORE WILLARD CASE, OF AUBURN, NEW YORK. ASSIGNOR TO CASE RESEARCHLABORATORY INCORPORATED, 0F AUBURN, NEW YORK, A CORPORATION NEW YORK.

METHOD OF PRODUCING SLOT UNITS.

This invention relates to a certain new and improved method of producingan apparatus for taking, printing, or reproducing a film record, andmore specifically to a method of manufacturing an apparatus for` use inproducing a film record of light variations as caused by electricvariations preferably corresponding to sound wave variations, as forinstance, articulate sound waves.

In apparatus of this character for producing or reproducing a filmrecord of light variations, it has been customary to move the film pasta small printing slot in a wall disposed between the film and a sourceof light, and it is preferable that the film move past the 'slot insubstantial Contact with the Wall so that only the' portion of the filmdirectly in V-front of the slot is exposed to the light emanating fromthe source, altho some spacing is possible under various conditions.

Considerable difficulty has been experienced in producing an accurate,clear and exact lm record, and also in reproducing accurately theoriginal sound from a record, due to the fact that dust, film material,or foreign matter collects in the slot,--more particularly is scrapedoff the film record or ragged along by it as it passes by the edge ofthe slot, and this foreign material partially obstructs the slot whichis extremely small, and may be of various forms and shapes for differentpurposes, as for illustration, .001 of an inch in Width and .1 of aninch in length, when used in taking or reproducing talking pictures, orthe slot or slit may be round or square and of very small area, as forinstance, in picture transmission or reception. And the result is thatthe film record produced is somewhat unsatisfactory because of thisobstruction of t-he slot, and for the same reason a reproduction of evena perfect film record or picture i is unsatisfactory.

The object of this invention is the production of a method ofmanufacturing a slit or slot unit, retaining all of the advantages ofthe present similar apparatus, but avoiding or partially avoiding thedisadvantages above set forth.

More specifically this invention is addressed to a method of producing aslotcontaining unit in itself of novel construction, and adapted for usein either picturetaking or picture reproducing apparatus, or

an apparatus for producing a film record of f light-variations aseffected by electrical variations corresponding to articulate soundWaves or musical tones.

Figure 2 is an elevation of a portion of the slot-containing unit ofthis invention."

Figures 3, 4, 5, 6 and 7 are sectional views illustrating the separatesteps of the method of this invent-ion.

Figure 8 is a section taken at right angles to Fig. 7.

Figure 9 is a view of a modified form of unit.

In a general way, the structure of Figure 1 is the same as thatdisclosed in my application Serial No. 719,098, filed June 10, 1924, andcomprises a variable source of cathode rays including two spacedelectrodes 2,- and -3- enclosed in a bulb -1-, the electrodes beingconnected in circuit with a source of potential as a battery -4- and asecondary -5- of a transformer, the pri-" mary -6- of which is connectedin circuit with a source of potential --7- across the filament -8- andplate -9- of a spacedischarge device -10-, the grid -11 of which isconnected in circuit with the {ilament -8- and the secondary 39- of atransformer, the primary -41- of which is connected in circuit with asource of potential, as a battery -42- and a microphone -43-.

In a general way, this structure includes y means for varying anelectric current in accordance with sound-wave variations, and

Yfor amplifying such variations, and thereby effecting amplifiedvariations in the source of light -1-, the light rays emanating fromwhich are adapted to be printed or photographed upon the film -18-moving past the narrow slot 14- in the slot-containing unit -.15-. Thisslot-containing 'unit 15 may be a portion of an enclosure for the Whenthethm coating of op film. or a portion of an enclosure for the lamp,and takes vthe place of the ordinary portion of a photographingapparatus or reproducing apparatus which contains the usual' slot pastwhich it is quite essential that the film should move 'in tight relationwith the walls bordering the slot.

This slot-containing unit is of novel manufacture and construction, andas. here shown, consists of a sheet of transparent ma- -teria1, as thequartz or ls sheet -16- of an suitable shape an size, and the word g assas used in rthe specification and vclaims hereof is deemed to includequartz.

Upon'one face .of the piece of glass 16 there is formed a layer 17 ofopaque material, such as metal, and perhapspreferably silver produced insuch a wa that the metal is strongly adhered to t e glass. The

20 opaque material should be de osited on thevglass in the formy ofminute y sub-divided particles and preferably this layer of opaquematerial, such as silver, ma perhaps preferably be evaporated upon t eglass, or may '.25 be electrically, chemically, orby cathode sputteringdeposited thereon so as to form 1a very thin coating or sheet of metal uone side of and firmly adhered to the su the theglass late -16-.

Any suitab e opaque material may be utilized for this purpose, but Ihave found that silyer eiects a ve satisfactory result. very thin layerof eposited silver, less than .OOLof an inch in thickness, andpreferably less than .0005 of an inch in thickness, is highly ellicientfor my purpose. In the drawings it has been desirable to greatlyexaggerate the thickness of the component parts for the purpose ofclarity.

ue material has been produced upon the g assin any suitable manner, asforinstance, one ofthose s described, a slot or slit is ruled in themetal, or in other Words, a small portion of the L5 metal is scraped olfthe glass so as to expose a portion of the glass late through the metal,and this may be e ected in any suitable Way, but in such a manner as notto scratch` the glass or other transparent support, as

i $0 by.a metal tool .or diamond point orjthe like, so as to produce aslot or ope through the metal of a. proper length ang width, a sizesuitable for this purpose being of aninch in width and .1 of an S5 inch1n length when used for talking picture Awork. l ilfter. a sharplydefined slot 14 as described, has been formed through the opaque coating17, this slot is covered by a strip For oo sheet 18 of glass, quartz orsimilai` material, and the termfglass as used in the claims 'hereofisdeemed to include quartz, and this strip 18 of glass may be secured tothe opatpie coating 17 in any suitable manner, as y transparent cement,such as t K Canada balsam.. This stri or sheet 18 of glass may be of anysuita le area so long as it is largerL than the slot 14 and completelycovers the slot. The glass sheet 18 may be of a thiclmessadapting it forhandling,

and` for securement tothe metallic or opaque layer 17 without breaking,and for that `reason is, when secured in place cons lderably thickerthan iiicient use in the finlshed roduct permits, and for that reasonafter being secured in position, as perhaps best illustrated in Fi re 6,thev comparatively thick sheet of gass 18 is subjected lto a grindingoperation which can be eiected in any suitable manner, by an suitableand well known tools so that its t ickness is reduced to substantiall.001 ofa'n inch, 'or less, v

whereupon the pro uct is in condition for eiiicient and satisfactoryuse.

Figure 3 illustrates the. glass backin or sheet 16 .which need notnecessarily be g ass, but may be of any suitable transparent maltei'ial.In Fig. 4 the metallic coating 17 is illustrated as deposited upon thesheet 16. In Figure 5 the `slot 14 is ruled in the opaquen coating 17.Figure 6 shows theA comparatively thicker sheet of glass 18 as.

secured in place across the slot, while Figure 7 illustrates the sheet18 as ground down to the desired thickness for the completed product.Figure 9 illustrates 'a modified A sformin which the glass`support 16 isin the formof a segment of a cylinder, and the covering plate 18 isconcave to fitvthe d deposited opaque layer and ,flat upon its frontface with its edges rounded ofi'.

The method here described is peculiarly. ciiicient for the production ofthe product described, in that by this means a highly efficient slot orslit 2is produced which is entirely protected from the entry of foreignmaterial, and by means of a lassv late upon the side toward the film wch is of such exceeding thinness as to he practically negligent ineffecting the passage of the lm across the slot unit, and altho I haveshown and described a specific method of producing-the slot unitdescribed, I do not desire to restrict myself to the details of themethod except as the same may be specifically set forth in the claimshereto appended.

.I claimz- 1. The method of producing a slot-containing uiiit comprisingforming'a layer of an opaque material upon a transparent-backound,forming a narrow elongated slot in the opaque layer to expose thetransparf w ent background, Acovering'the side of the slot oppositeA thetransparent background with a sheet of glass, `and then the lass sheetto the thickness desired.

2. he method of producing a slot containing unit comprising forming a'.la er of an opaque material with a slot therein, securing a sheet oftransparent material across lio the slot and then grinding the sheetoftransthe open side of the slot lwith a glass sheet, parent material toya thickness not substanand then grinding the glass sheet to the tiallygreater than .005 of an inch. thickness desired. v 10 3. The method offorming a slot-con- In Witness whereof I have hereunto Set. 5 tainingunit Comprising a deposited layer of my hand this 25th day of May, 1925.silver upon a sheet of glass, forming a narrow slot in the layer ofsilver and covering THEODORE WILLARD CASE.

